Director of National Intelligence James Clapper claims the recent wave of leaks has done “huge, grave damage” to our intelligence gathering capabilities.

Nonsense, says Glenn Greenwald, the Guardian columnist who served as the primary conduit for the leaks: “There’s not a single revelation that we’ve provided to the world that even remotely jeopardizes national security.”

Somewhere in between those two takes lies the truth.

Intelligence experts and former officials interviewed by POLITICO say there will likely be some harm to U.S. intelligence efforts — though not in exactly the way many Americans might expect and not because the stories really revealed the crown jewels of American counter-terrorism efforts.

And the surest negative impact of the disclosures is more likely to fall on the U.S. Internet industry, as some of its international customer base flees in search of sites thought to be more secure from American government snooping.

Former officials say it’s not so much the specifics of what was leaked as the huge wave of publicity the leaks generated: Every news story could serve as a revelation to some terrorists, and a reminder to others, of the nation’s capabilities.

“It’s kind of Darwinian,” former National Security Agency Director Michael Hayden said. “The more stuff like this is in the public domain, we’ll still catch terrorists, but it will be the stupid terrorists. … The guys we should really be worried about will be far less likely to be swept up in this effort.”

While many Americans view terrorists as careful and well-informed, ex-intelligence officials say that in reality, their skill sets run the gamut — and the biggest terror threat in the United States right now actually seems to be homegrown extremists who are not hardened operatives and who lack first-rate tradecraft. These are the precisely the sorts of novices who could be tipped off or decide to behave more furtively precisely because of the recent spate of surveillance disclosures.

And, as Americans saw in April with the deadly attacks Tamerlan and Dzhokhar Tsarnaev allegedly carried out at the Boston Marathon, amateurs are still capable of inflicting serious damage.

“Intelligence agencies make a living off of other people’s mistakes,” said former NSA general counsel Joel Brenner. “You’d be surprised at how many people make mistakes.”

Hayden insists that even the wording in stories sometimes tips off terrorists. In the middle of the last decade, he ran off-the-record seminars for journalists at NSA headquarters, the New York Sun reported. He and others from the spy agency urged reporters to replace terms like “intercepts” in their stories with vaguer phrases like “intelligence reports.” Such seemingly minor changes affect the way targets of U.S. intelligence behave, he said.

Still, there remains considerable dispute about whether the harm in the recent wave of leaks comes directly from the leaks themselves or from media coverage that has treated them as earth-shattering revelations.

Before the first leak last week about Verizon call data being gathered on a daily basis, there was ample reason for both privacy-sensitive Americans and well-informed terrorists to suspect that the government had been gathering a great deal of information on calling patterns — though how many in this country or overseas had absorbed that information is hard to assess.

“There are things that are available to be known that people don’t know,” Brenner said. “Part of the American public expressed shock this week at things that I would say were in the public domain.”

USA Today reported in 2006 that the U.S. government was getting a significant amount of call information from major U.S. phone companies. Denials by some of the companies made the story more murky, but other news outlets backed up the core point, and the Bush administration never really denied it.

Some at home and abroad may not have expected President Barack Obama to continue such an operation. But the idea that it had continued was not some flight of fancy, even before last week’s disclosure of the “top secret” court order to Verizon.

For one thing, several Senate Democrats had warned cryptically of secret legal orders that they said affected large numbers of Americans and would prompt outrage when disclosed — though critics of the programs note some in government have tried to undercut the suspicions about call-tracking operations by dissembling or even offering misleading answers.

Sens. Ron Wyden (D-Ore.) and Mark Udall (D-Colo.), who’ve been pressing for disclosure of the broad legal principles behind the program for several years, clearly don’t think disclosure of the call-tracking program will harm national security.

In one case, Wyden asked Clapper directly about precisely these types of programs at a March 2013 hearing: “Does the NSA collect any type of data at all on millions or hundreds of millions of Americans?”

“No, sir,” Clapper replied. He says now that he thought the question referred to collection of the content of Americans’ communications, not simply calling patterns.

The week’s second big disclosure, that the feds have installed equipment at major U.S. email and social media firms to provide a feed of Web traffic from overseas, is also something less than a sky-is-falling revelation. In 2008, the Senate debated and passed Foreign Surveillance Intelligence Act amendments that specifically authorized collection of information from foreign customers logging in from outside the United States — even those who had no suspected connection to terrorism.

The authority wasn’t slipped into the law unnoticed. In fact, some liberal House members, including then-House Judiciary Committee Chairman John Conyers (D-Mich.), introduced a bill in 2009 to essentially do away with bulk collection from foreign sources unless there was a specific suspicion about terrorism. The measure went nowhere.

And in 2010, a Freedom of Information Act lawsuit from the American Civil Liberties Union produced hundreds of pages of materials on the bulk collection provision known as Section 702. The documents, posted on the Web, say the FBI now has access to “a faster, less labor-intensive process involving fewer personnel.”

“User need not be a foreign power or agent of foreign power,” the FBI records say. “Without the need for individualized [Foreign Intelligence Surveillance Court] orders … significantly less documentation … no probable cause required.”

ACLU lawyer Alex Abdo said the recent leak about Section 702 was more upsetting than unexpected. “It is consistent with what we thought the government was doing,” he said. “Last week’s disclosure confirmed for us the government is engaging in the surveillance we most feared. Now, we know the mechanism for the surveillance, but the concern we have is just the same.”

Some say last week’s leak broke new ground with the description of a real-time or near real-time access to Internet firms’ data through a system known as PRISM. But the system and even its logo seem an awful lot like the “fiberoptic splitter” a whistleblowing AT&T employee described in a 2006 lawsuit as having been installed by the NSA at an AT&T switching station in San Francisco.

Hayden scoffs at claims that the leaks don’t really disclose anything all that new.

“You’ve been running these stories 24/7 on your news network for six days now. They’ve been at the top of the newspapers, above the fold of all the big dailies,” he noted. “Something tells me you think it’s news. So why wouldn’t some semi-literate, religious fanatic living in a cave in the Hindu Kush mountains? Why assume he knew all this was going on that you apparently didn’t?”

The impact, said Hayden, is magnified over time. “The more it’s public, it goes viral. It’s networked. It spreads throughout the network,” the former NSA chief added. “There may have been nodes in the network that were quite aware and nodes in the network that weren’t. That proportion is going to change.”

The conclusion that it’s not the details of the leaks but the net volume of publicity about surveillance that is harmful is awkward for Obama. His mantra has become that he “welcomes the debate” even though he doesn’t support the leaks.

But a protracted debate on the issue, as healthy as it may be for U.S. democracy, guarantees continued media coverage that keeps reminding terrorists and other bad actors that they need to take precautions to keep their operations secret.

That may be why, in his interview with NBC on Saturday, Clapper expressed concern about a “media explosion” leading terrorists to change their behavior.

“Transparency … is a great thing in this country, but that same transparency has a double-edged sword,” he said. “Our adversaries, whether nation-state adversaries or nefarious groups, benefit from that transparency. So as we speak, they’re going to school and learning how we do this.”

And even as they assess the damage done to-date, intelligence officials fear the worst could be yet to come. The source for the Guardian and Washington Post stories, Edward Snowden, has said he had access to a list of U.S. intelligence operatives and bases. In addition, he’s shared a huge trove of other documents with The Guardian that remain undisclosed, The New York Times reported.

Despite the fears for the future, the information published in the past week doesn’t seem to be catastrophic or terminal for the programs involved.

Unlike a leak to The Associated Press last year, which may have led to the termination of a U.S.-backed counterterrorism operation in Yemen, or a leak in 2009 to Fox News’s James Rosen, which may have put a human source inside North Korea in danger, there’s every indication the call-tracking program and the interception of foreign users of U.S. Web firms is going to continue.

They may well be less effective — but to what degree isn’t yet known and is probably unknowable to any significant degree of certainty.

Part of any estimate of the future damage will have to look at what intelligence the programs have provided in the past.

Senate Intelligence Committee Chairwoman Dianne Feinstein (D-Calif.) and House Intelligence Committee Chairman Mike Rogers (R-Mich.) have said the call-tracking program helped prosecute a participant in the deadly Mumbai rampage in 2008 and helped head off a plot to bomb the New York City subways in 2009.

And Feinstein said there were more successes she could not outline publicly.

“The instances where this has produced good — has disrupted plots, prevented terrorist attacks — is all classified, that’s what’s so hard about this. So that we can’t actually go in there and other than the two that have been released give the public an actual idea of people that have been saved, attacks that have been prevented, that kind of thing,” she said Sunday on ABC’s “This Week.”

Still, skeptics such as Udall look at the same facts without seeing the same utility.

“I am not convinced that it’s uniquely valuable intelligence that we could not have generated in other ways,” Udall told ABC.

While Clapper has pointed to some terrorism-related successes that could be impacted by the leaks, he’s also suggested that the damage could be felt in other areas. The PRISM program is used to search not only for suspected terrorist communications but also data on nuclear proliferation, cyberattacks and foreign governments’ intelligence operations.

Former officials said major intelligence services like those operated by the Chinese and the Russian governments probably didn’t learn anything new from the intelligence programs that were the subject of leaks last week. However, the large powers may have picked up diplomatic leverage from the apparently related leak of a top-secret Obama directive ordering officials to draw a list of potential targets for cyberwarfare.

The most certain impact of disclosures may be a loss of business for U.S. Internet and social media firms. One of the PowerPoint pages disclosed by The Guardian lists services such as Gmail, Yahoo, Hotmail and Skype. Privacy-sensitive users in places like Europe may try to find other providers. That could strengthen those foreign businesses and lead to more Web content being harder for U.S. intelligence to reach or even winding up beyond its reach.

“We just punished American businesses who are just obeying U.S. law,” Hayden said.

However, Brenner said if terrorists decide not to communicate via the Internet or phones, that could carry some benefits by impeding their operations.

“If you’re able to drive your opponents completely off the network, you’ve lost something because they are are harder to track,” he said. “On the other hand, you’ve made them resort to very ineffective, old-fashioned forms of communication.”